New England Dog Whelk (Nassarius trivittatus)
Color: The shell ranges in color from white
to yellowish grey to dark reddish brown, and occasionally has brown spiral stripes.
Size: 1-inch long, 1/2-inch wide.
Habitat: Rocky, sandy, shallow intertidal areas.
Seasonal appearance: All year.
New England dog whelks are small snails distinguishable by their pointed spiral shells, which have raised beads along the ridges and sharp, scalloped outer lips.
Life History and Behavior
Rarely found as solitary animals, this species of whelk is often found in groups of many individuals. New England dog whelks are scavengers as well as predators. They feed mostly on dead fish but are capable of drilling holes in the shells of bivalves using an organ called the radula. The radula is a tooth-covered drill used to bore a small hole into the hard shell of other mollusks. After drilling the hole, the New England dog whelk can feed upon the soft flesh of its prey. When feeding on barnacles, however, the New England dog whelk will pry open the top plates rather than drill a hole.
The color and shape of the New England dog whelk differs depending on the geographical location and the prey consumed. Those that eat mussels are predominately dark reddish brown, while whelks that consume barnacles are white to light yellowish-brown. New England dog whelks living in high-energy environments, such as beaches, have smaller ridges than those living in marshes and inlets.
Adapted from The Uncommon Guide to Common Life on Narragansett Bay. Save The Bay, 1998.